What happens?
PLC processing stops with a watchdog exception (task overflow).
When does this behaviour occur?
Using functions from the 'SysTimeRTC' library may sporadically lead to a runtime extension of several milliseconds. In this case, a task overflow may occur and, if the watchdog is activated, a watchdog exception will be triggered.
Which products are affected?
c300 controller from V3.0
p300 panel controller from V3.0
Short-term measures:
If possible, use the functions of the CAA libraries (e.g. CAA DTUtil). If an accuracy of 1s is not enough, do not use the functions of the 'SysTimeRTC' library in tasks requiring an equidistant processing behaviour (e.g. motion tasks) or monitored by a watchdog.
Evaluation/recommendations:
The 'SysTimeRTC' library contains functions to read out the value of the real-time clock in high resolution. Functions of this library can, however, lead to a task overflow as a result of which PLC processing may be stopped.
